movq %rcx,RIP-ARGOFFSET(%rsp)
CFI_REL_OFFSET rip,RIP-ARGOFFSET
GET_THREAD_INFO(%rcx)
- testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP), \
- TI_flags(%rcx)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
jnz tracesys
cmpq $__NR_syscall_max,%rax
ja badsys
FIXUP_TOP_OF_STACK %rdi
movq %rsp,%rdi
call syscall_trace_enter
- LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */
+ /*
+ * Reload arg registers from stack in case ptrace changed them.
+ * We don't reload %rax because syscall_trace_enter() returned
+ * the value it wants us to use in the table lookup.
+ */
+ LOAD_ARGS ARGOFFSET, 1
RESTORE_REST
cmpq $__NR_syscall_max,%rax
ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_REST
/* Check for syscall exit trace */
- testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx
+ testl $_TIF_WORK_SYSCALL_EXIT,%edx
jz int_signal
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call syscall_trace_leave
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
- andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi
+ andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
jmp int_restore_rest
int_signal:
/* runs on exception stack */
KPROBE_ENTRY(debug)
INTR_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_debug, DEBUG_STACK
/* runs on exception stack */
KPROBE_ENTRY(nmi)
INTR_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
pushq $-1
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_nmi, 0, 0
KPROBE_ENTRY(int3)
INTR_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_int3, DEBUG_STACK
/* runs on exception stack */
ENTRY(double_fault)
XCPT_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
paranoidentry do_double_fault
jmp paranoid_exit1
CFI_ENDPROC
/* runs on exception stack */
ENTRY(stack_segment)
XCPT_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
paranoidentry do_stack_segment
jmp paranoid_exit1
CFI_ENDPROC
/* runs on exception stack */
ENTRY(machine_check)
INTR_FRAME
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_machine_check
sysret
CFI_ENDPROC
ENDPROC(ignore_sysret)
+
+#ifdef CONFIG_XEN
+ENTRY(xen_hypervisor_callback)
+ zeroentry xen_do_hypervisor_callback
+END(xen_hypervisor_callback)
+
+/*
+# A note on the "critical region" in our callback handler.
+# We want to avoid stacking callback handlers due to events occurring
+# during handling of the last event. To do this, we keep events disabled
+# until we've done all processing. HOWEVER, we must enable events before
+# popping the stack frame (can't be done atomically) and so it would still
+# be possible to get enough handler activations to overflow the stack.
+# Although unlikely, bugs of that kind are hard to track down, so we'd
+# like to avoid the possibility.
+# So, on entry to the handler we detect whether we interrupted an
+# existing activation in its critical region -- if so, we pop the current
+# activation and restart the handler using the previous one.
+*/
+ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
+ CFI_STARTPROC
+/* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
+ see the correct pointer to the pt_regs */
+ movq %rdi, %rsp # we don't return, adjust the stack frame
+ CFI_ENDPROC
+ CFI_DEFAULT_STACK
+11: incl %gs:pda_irqcount
+ movq %rsp,%rbp
+ CFI_DEF_CFA_REGISTER rbp
+ cmovzq %gs:pda_irqstackptr,%rsp
+ pushq %rbp # backlink for old unwinder
+ call xen_evtchn_do_upcall
+ popq %rsp
+ CFI_DEF_CFA_REGISTER rsp
+ decl %gs:pda_irqcount
+ jmp error_exit
+ CFI_ENDPROC
+END(do_hypervisor_callback)
+
+/*
+# Hypervisor uses this for application faults while it executes.
+# We get here for two reasons:
+# 1. Fault while reloading DS, ES, FS or GS
+# 2. Fault while executing IRET
+# Category 1 we do not need to fix up as Xen has already reloaded all segment
+# registers that could be reloaded and zeroed the others.
+# Category 2 we fix up by killing the current process. We cannot use the
+# normal Linux return path in this case because if we use the IRET hypercall
+# to pop the stack frame we end up in an infinite loop of failsafe callbacks.
+# We distinguish between categories by comparing each saved segment register
+# with its current contents: any discrepancy means we in category 1.
+*/
+ENTRY(xen_failsafe_callback)
+ framesz = (RIP-0x30) /* workaround buggy gas */
+ _frame framesz
+ CFI_REL_OFFSET rcx, 0
+ CFI_REL_OFFSET r11, 8
+ movw %ds,%cx
+ cmpw %cx,0x10(%rsp)
+ CFI_REMEMBER_STATE
+ jne 1f
+ movw %es,%cx
+ cmpw %cx,0x18(%rsp)
+ jne 1f
+ movw %fs,%cx
+ cmpw %cx,0x20(%rsp)
+ jne 1f
+ movw %gs,%cx
+ cmpw %cx,0x28(%rsp)
+ jne 1f
+ /* All segments match their saved values => Category 2 (Bad IRET). */
+ movq (%rsp),%rcx
+ CFI_RESTORE rcx
+ movq 8(%rsp),%r11
+ CFI_RESTORE r11
+ addq $0x30,%rsp
+ CFI_ADJUST_CFA_OFFSET -0x30
+ pushq $0
+ CFI_ADJUST_CFA_OFFSET 8
+ pushq %r11
+ CFI_ADJUST_CFA_OFFSET 8
+ pushq %rcx
+ CFI_ADJUST_CFA_OFFSET 8
+ jmp general_protection
+ CFI_RESTORE_STATE
+1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
+ movq (%rsp),%rcx
+ CFI_RESTORE rcx
+ movq 8(%rsp),%r11
+ CFI_RESTORE r11
+ addq $0x30,%rsp
+ CFI_ADJUST_CFA_OFFSET -0x30
+ pushq $0
+ CFI_ADJUST_CFA_OFFSET 8
+ SAVE_ALL
+ jmp error_exit
+ CFI_ENDPROC
+END(xen_failsafe_callback)
+
+#endif /* CONFIG_XEN */
git.samba.org / sfrench / cifs-2.6.git / blobdiff